Michael asks for a list, short or long, of books that have influenced my study of society. A tall order. Here are a few suggestions [since I do not read very much, I am very bad at suggesting bibliography, but much of what I read has a big effect on me -- otherwise I do not read it -- so these are all worth a look, in my judgment.]
As Michael indicates, Volume One of CAPITAL by Marx looms large for me. There is a good deal by Marx that is worth reading, including his letters to and from Engels, but certainly read THE COMMUNIST MANIFESTO. For sheer fun, not to learn anything much, read THE HOLY FAMILY, a youthful attack by Marx and Engels on some of their fellow left Hegelians.
Getting serious now:
I strongly recommend reading some Freud. Long and difficult as it is, THE INTERPRETATION OF DREAMS is well worth the effort. With it, read Richard Wollheim's splendid book, SIGMUND FREUD for an overview. Then read Erik Erikson's CHILDHOOD AND SOCIETY, one of the loveliest books ever written. I learned a great deal from it. For fun, read some Erving Goffman. He wrote several short books [THE PRESENTATION OF SELF IN EVERYDAY LIFE, ASYLUMS, among others], and they are all worth reading.
Anything by Nobel laureate Amartya Sen, who all by himself has redeemed the Economics Nobel Prize from ignominy. The serious study of economics is, of course, essential to an understanding of society. For an analytical exposition of the Classical Political Economists -- Smith, Ricardo, Marx -- I really think you cannot do better than my book, UNDERSTANDING MARX.
This may strike some of you as odd, but I would strongly recommend spending time reading serious history -- especially the sort of institutional history written by the great historians of the ancient and medieval worlds. My own reading of history has been heavily tilted toward the history of Western Europe, but you ought also to read something about the history of China and the history of Islam. The libraries are filled with wonderful books of serious history, and I have only scratched the surface. If anyone is interested, I will be happy to mention some of the books I found especially fascinating.
During most of my life, I found American history utterly boring, but once I joined the Afro-American Studies Department at UMass and started to read the history of African-Americans, my attitude changed completely. There again, if anyone is interested, I will be happy to suggest ten or fifteen titles, all well worth the effort, beginning with W. E. B. Du Bois's classic work, BLACK RECONSTRUCTION IN AMERICA: 1860-1880.
Well, that should keep Michael busy for a while.